[Feature Request] Overhaul command handling system to utilize decorators instead of 'cmd_' method name prefixes

It might be a better idea to change the command handling system so that it uses a `@command` decorator instead of the current `cmd_` prefix on methods. This would also open up the opportunity to add other custom decorators for other functionality.
For example:
```
OLD:
def cmd_echo(...):
    ...

NEW:
@command
def echo(...):
    ...
```